“Many Varieties of Beautiful Inheritance,” Historian Ruth Schwartz Cowan

In her essay, “Many Varieties of Beautiful Inheritance,” Historian Ruth Schwartz Cowan describes the various forms of eugenics that became popular throughout the world in the first half the twentieth century. Please answer the following question in essay form.
How did eugenics borrow on the evolving sciences of heredity to become a vast popular movement in the United States and other countries, and why did it take the forms that it did in different countries? In your response, you must compare at least two countries or parts of the world since eugenic ideas and practice varied considerably in different places.